python中的typing库

typing的主要作用有：

1. 类型检查，防止运行时出现参数、返回值类型不符
2. 作为开发文档附加说明，方便使用者调用时传入和返回参数类型
3. 模块加入不会影响程序的运行不会报正式的错误，pycharm支持typing检查错误时会出现黄色警告

语法：

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def 函数名(参数: 数据类型) -> 返回值类型:     pass   变量名: 数据类型 = 值

　　

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from typing import Sequence  # 这个用来存放一堆定义的类型     from typing import NewType # 用来创建一个新的类型，以便后续可以使用这个来规范类型

　　

Any　　任意类型

Union[X,Y]　　联合类型，X或Y

Option[X]　　可选类型，X或None

Tuple[X,Y]　　元组类型， 第一个元素X，第二个元素Y， 

Callable[[X], Y]　　可调用类型，第一个是参数列表，第二个是返回类型

 

typing包含的类型

+ View Code?

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AbstractSet = typing.AbstractSet Any = typing.Any AnyStr = ~AnyStr AsyncContextManager = typing.AbstractAsyncContextManager AsyncGenerator = typing.AsyncGenerator AsyncIterable = typing.AsyncIterable AsyncIterator = typing.AsyncIterator Awaitable = typing.Awaitable ByteString = typing.ByteString Callable = typing.Callable ClassVar = typing.ClassVar Collection = typing.Collection Container = typing.Container ContextManager = typing.AbstractContextManager Coroutine = typing.Coroutine Counter = typing.Counter DefaultDict = typing.DefaultDict Deque = typing.Deque Dict = typing.Dict FrozenSet = typing.FrozenSet Generator = typing.Generator Hashable = typing.Hashable ItemsView = typing.ItemsView Iterable = typing.Iterable Iterator = typing.Iterator KeysView = typing.KeysView List = typing.List Mapping = typing.Mapping MappingView = typing.MappingView MutableMapping = typing.MutableMapping MutableSequence = typing.MutableSequence MutableSet = typing.MutableSet NoReturn = typing.NoReturn Optional = typing.Optional Reversible = typing.Reversible Sequence = typing.Sequence Set = typing.Set Sized = typing.Sized TYPE_CHECKING = False Tuple = typing.Tuple Type = typing.Type Union = typing.Union ValuesView = typing.ValuesView